The present invention relates to an apparatus for displaying movement information, and more particularly to an apparatus that analyzes a movement waveform that is acquired by a movement sensor, and displays quantitative movement information.
The Parkinson's disease is an incurable disease that a lesion develops in a substantial nigra or striate body within brains which control a movement, and causes ataxia of involuntary movement such as walking. Also, since it is a progressive disease, when the Parkinson's disease is untreated for about ten years, they say that a patient becomes bedridden. Thus, early diagnostic and treatment have been demanded.
However, the Parkinson's disease cannot be diagnosed by a blood test or diagnostic imaging regardless of a brain disease, and in the current state, the severity (progression stage) of the disease state is determined according to specific clinical manifestations (tremor, muscular rigidity, akinesia, pause retaining disorder, etc.) and patient's complaint. In the above determining method, it is difficult to quantitatively evaluate the severity of the disease state, and information for realizing appropriate medications is not satisfactory.
Up to now, in order to quantitatively evaluate the severity of the Parkinson's disease, a method of tapping the keyboard of a computer has been frequently studied (for example, refer to Movement Disorder vol. 15, No. 1, 2000, pp. 36 to 47). According to this method, the movement of a patient's fingers can be simply evaluated as on and off states.
Also, as another method, there is disclosed a manner in which a device for depressing a button is simply structured as with the keyboard, and a timing at which the button is depressed is measured (for example, refer to U.S. Pat. No. 6,416,485 B1). According to this method, the movement of a patient's fingers can be evaluated as on and off states as with the evaluation using the keyboard.
In addition, in the field of an input device for sign language, there is disclosed a method in which a primary winding is first excited, and a movement is detected by an arrangement of a magnetic response member and a secondary winding, to thereby evaluate the hooking and stretching of fingers (for example, refer to JP 2003-15810A). That is, in the invention disclosed in JP 2003-15810A, a transmitter coil is disposed in each of the fingers, and a receiver coil is disposed on a palm of the hand. Then, an AC current different in frequency is allowed to flow in each of the transmitter coils, and an induced electromotive force that has been obtained by the receiver coil on the palm of the hand is detected by a frequency detector circuit to detect which finger comes in contact with the palm.
Those three methods can acquire the movement of the fingers as digital on/off information.
On the other hand, as a method of evaluating the movement of fingers in an analog fashion, there has been reported a method of detecting the movement of fingers from an image obtained by a camera, which is called “optoelectronic camera system” (for example, refer to Movement disorder vol. 12, No. 5, 1997, pp. 665 to 676). According to the above method, the movement of fingers can be accurately detected.
Also, in the field of a metal detecting apparatus, as a method of detecting a metal substance that moves between a fixed exciting circuit and a detection coil, there is disclosed a method in which a variation of an eddy current that is detected by the detection coil is detected by a detector circuit, and the metal substance is detected through a low pass filter (for example, refer to JP Hei 5-5784A). According to the above method, the movement of the metal substance can be monitored.
In addition, the present inventors have discloses a magnetic sensor type finger tapping measuring device as a movement sensor that appropriately measures waveform data (for example, refer to Neurosci. Res. vol. 49, No. 2, 2004, pp. 253 to 260). That is, the device disclosed in the above publication is designed such that a coil that transmits a magnetic field of a high frequency (20 kHz) and a coil that receives the high frequency are put on fingers, an induced electromotive force of the high frequency magnetic field is detected by the receiver coil, detection is conducted by the frequency of the high frequency magnetic field, and filtering is conducted. Thereafter, recording is conducted as a digital signal by an AD converter of a notebook computer.
Those three methods can acquire the movement of fingers as analog information.